<!DOCTYPE html>
<html lang="zh">
<head>
    <meta charset="UTF-8">
    <title>01-line-height_02-应用</title>
    <style>
        div {
            background-color: #ff0;
            width: 200px;
            height: 50px;
            line-height: 50px;
        }
    </style>
</head>
<body>

<div>我是div</div>
    

</body>
</html>